Key Laboratory of Ministry of Education for TCM Viscera-State Theory and Applications, Liaoning University of Traditional Chinese Medicine, Shenyang, China.
The First Medical College, Guangzhou University of Chinese Medicine, Guangzhou, China.
Front Immunol. 2020 Sep 10;11:2175. doi: 10.3389/fimmu.2020.02175. eCollection 2020.
Exosomes are nanosized vesicles secreted by most cells, which can deliver a variety of functional lipids, proteins, and RNAs into the target cells to participate in complex intercellular communications. Cells respond to certain physical, chemical, and biological stimuli by releasing exosomes. Exosomes are rich in small molecules of RNA, including miRNAs and mRNAs, which have been demonstrated to have certain functions in recipient cells. Recent studies on single-cell RNA sequences have revealed the transcription and the heterogeneity of macrophages in Ldlr-/-mice fed with a high-fat diet. Five macrophage populations were found in the atherosclerotic plaques. It is worth noting that these subset populations of macrophages seem to be endowed with different functions in lipid metabolism and catabolism. A total of 100 differentially expressed mRNAs were selected for these subset populations. Importantly, these macrophage populations were also present in human advanced atherosclerosis. To clarify the specific functions and the regulatory mechanism of these macrophage populations, we extracted exosome RNAs from the plasma of patients with chronic coronary artery disease (CAD) and performed RNA sequencing analysis. Compared with the healthy control, a total of 14 miRNAs were significantly expressed in these patients. A total of 5,248 potential mRNAs were predicted by the bioinformatics platform. Next, we determined the outcome of the intersection of these predicted mRNAs with 100 mRNAs expressed in the above-mentioned five macrophage populations. Based on the screening of miRNA-mRNA pairs, a co-expression network was drawn to find out the key RNAs. Three down-regulated miRNAs and five up-regulated mRNAs were selected for validation by real-time RT-PCR. The results showed that the expression of miR-4498 in plasma exosomes was lower than that in the healthy control, and the expressions of Ctss, Ccr2 and Trem2 mRNA in peripheral blood mononuclear cells isolated from CAD patients were higher. In order to clarify the regulatory mechanism, we established a co-culture system . Studies have shown that the uptake of exosomes from CAD patients can up-regulate the expression of Ctss, Trem2, and Ccr2 mRNA in THP-1 cells induced by lipopolysaccharide. Our findings revealed a unique relationship between the transcriptional signature and the phenotypic heterogeneity of macrophage in the atherosclerotic microenvironment.
外泌体是大多数细胞分泌的纳米大小的囊泡，可以将各种功能脂质、蛋白质和 RNA 递送到靶细胞中，参与复杂的细胞间通讯。细胞通过释放外泌体对某些物理、化学和生物刺激做出反应。外泌体富含小分子 RNA，包括 miRNA 和 mRNA，已被证明在受体细胞中具有某些功能。最近对单细胞 RNA 序列的研究揭示了高脂饮食喂养的 Ldlr-/-小鼠巨噬细胞的转录和异质性。在动脉粥样硬化斑块中发现了 5 种巨噬细胞群体。值得注意的是，这些巨噬细胞亚群似乎在脂质代谢和分解代谢中具有不同的功能。总共选择了 100 个差异表达的 mRNA 用于这些亚群。重要的是，这些巨噬细胞群体也存在于人类晚期动脉粥样硬化中。为了阐明这些巨噬细胞群体的具体功能和调节机制，我们从患有慢性冠状动脉疾病 (CAD) 的患者的血浆中提取外泌体 RNA，并进行 RNA 测序分析。与健康对照组相比，这些患者中共有 14 个 miRNA 显著表达。生物信息学平台共预测到 5248 个潜在的 mRNA。接下来，我们确定了与上述 5 种巨噬细胞群体中表达的 100 个 mRNA 相交的结果。基于 miRNA-mRNA 对的筛选，绘制了一个共表达网络，以找出关键的 RNA。通过实时 RT-PCR 对 3 个下调的 miRNA 和 5 个上调的 mRNA 进行了验证。结果表明，血浆外泌体中 miR-4498 的表达低于健康对照组，而从 CAD 患者外周血单核细胞中分离的 Ctss、Ccr2 和 Trem2 mRNA 的表达较高。为了阐明调节机制，我们建立了一个共培养系统。研究表明，来自 CAD 患者的外泌体的摄取可以上调脂多糖诱导的 THP-1 细胞中 Ctss、Trem2 和 Ccr2 mRNA 的表达。我们的研究结果揭示了动脉粥样硬化微环境中巨噬细胞转录特征与表型异质性之间的独特关系。
